Ecchordosis Physaliphora is a benign remnant derived from the notochord that is located along the craniospinal axis.

Malignant counterpart: chordoma


The lesion is typically asymptomatic and may be first recognized on imaging studies.


Usual location: level of clivus or sacrum


Size: usually less than 6 mL; if > 6 mL termed giant


Imaging studies:

(1) hypointense on T1 and hyperintense on T2

(2) non-enhancing with gadolinium

(3) bony pedicle (stalk) with focal bone destruction


Histologic features:

(1) physalliphorous cells with large intracytoplasmic mucin-containing vacuoles in a myxoid amphophilic matrix

(2) hypocellularity

(3) absent or rare mitoses

(4) minimal pleomorphism

(5) absence of tumor necrosis



(1) cytokeratin positive

(2) brachyury positive (encoded by TBXT gene)

(3) GFAP negative

(4) Ki67 less than 1%

To read more or access our algorithms and calculators, please log in or register.